Tire condition assessment instrument

ABSTRACT

A tire maintenance gauge including a first sensor engageable with a tire to measure a first tire parameter. A first indicator is movable in response to the measured first tire parameter. A second sensor is engageable with the tire to measure a second tire parameter. A second indicator is movable in response to the measured second tire parameter.

BACKGROUND

The present invention generally relates to measuring instruments, and particularly to a measuring instrument suited to measuring at least two parameters indicative of the condition of a vehicle tire.

Inflated rubber (synthetic as well as natural) tires are commonly used as the interface between vehicles and road surfaces. Inflated rubber tires absorb some of the bumps encountered on the road, while additionally improving the traction between the vehicle and the road. Tires are often provided with a tread that functions to redirect water and other road debris to improve the traction between the tire and the road. To improve tire performance, tires should be properly inflated and should include sufficient tread to provide the desired traction.

Tire inflation and tread condition are especially important for motorcycles where only two tires contact the road. The recommended tire pressure for a motorcycle may vary greatly as a function of the load on the tires (e.g., one rider or two riders) or the riding conditions (e.g., dry pavement vs. wet pavement). As such, it is important to frequently check the tire pressure.

Furthermore, excessive tread wear may reduce the traction achieved when riding a motorcycle, especially during adverse weather conditions (e.g., rain, snow, sleet, and the like). Therefore, it is important that the rider also monitor the tread condition on tires.

SUMMARY

The present invention generally provides a gauge that is capable of measuring two parameters that are indicative of tire condition. Generally, these parameters include the tire pressure and the tread depth. By combining a pressure gauge and a tread depth gauge into a single device, the space occupied by the measuring devices is reduced when compared to two separate gauges. In addition, the combination makes it more likely that a rider will measure both parameters simultaneously rather than just one of the two. This will give the rider a more complete picture of the condition of the tires. The tread depth gauge also indicates the relative condition of the tire using a color-coded tread depth scale. The color-coded scale makes interpretation of the results easy for the rider.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figures in which:

FIG. 1 is a perspective view of a motorcycle;

FIG. 2 is a perspective view of an instrument engageable with a tire and operable to measure two tire parameters;

FIG. 3 is a partial broken away front view of the instrument of FIG. 2 illustrating one sensor suited to measuring a tread depth;

FIG. 4 is a partial broken away rear view of the instrument of FIG. 2 illustrating one sensor suited to measuring a pressure;

FIG. 5 is a front view of a portion of the instrument of FIG. 2; and

FIG. 6 is a perspective view of another instrument engageable with a tire and operable to measure two tire parameters.

Before any embodiments of the invention are explained, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof is meant to encompass the items listed thereafter and equivalence thereof as well as additional items. The terms “connected,” “coupled,” and “mounted” and variations thereof are used broadly and encompass direct and indirect connections, couplings, and mountings.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a motorcycle 10 having a frame 15, and an engine and transmission assembly 20 mounted to the frame 15. A steering assembly 25 is pivotally mounted to the frame 15 and a front wheel 30 is rotatably mounted to the steering assembly 25 to support the front of the motorcycle 10. A rear wheel 35 is rotatably interconnected with the frame 15 and supports the rear of the motorcycle 10. The rear wheel 35 is driven by operation of the engine and transmission assembly 20. Each of the front and rear wheels 30, 35 includes a tire 40 that is filled with high-pressure air. In general, the recommended air pressure within the tires 40 is above 20 pounds per square inch (psi) with higher pressure being common and lower pressure being possible. Each tire 40 includes a fill valve 45 that is engageable with a standard fill valve fitting 50 (similar to the one shown in FIG. 2) to fill the tire 40 with compressed air. The fill valve 45 can also be used to release air from the tire 40 if desired.

FIG. 2 illustrates an instrument 55 that measures two parameters that are indicative of tire condition. The instrument 55 includes a housing 60 that substantially contains a tire pressure gauge 65 or sensor and a depth gauge 70 or sensor. The tire pressure gauge 65 measures the internal tire pressure and the depth gauge 70 measures the depth of the tread on the tire. The instrument 55 also includes a faceplate 75 that includes a first indicator in the form of a first needle 80 and a pressure scale 85 associated with the first needle 80. The first needle 80 moves in response to the measured pressure. The faceplate 75 further includes a second indicator in the form of a second needle 90 and a depth scale 95 associated with the second needle 90. The second needle 90 moves in response to the measured tread depth. Other constructions may use other indicators such as, but not limited to, analog or digital readouts.

As shown in FIGS. 2 and 4, the tire pressure gauge 65 includes a flexible hose 105 having a fill valve fitting 50 at one end. The fill valve fitting 50 engages the fill valve 45 of the tire 40 and opens the valve 45. While many angles are possible for the valve fitting 50, preferred constructions use a valve fitting 50 that is oriented at 90 degrees or 45 degrees relative to the flexible hose 105. Thus, high-pressure air from within the tire 40 flows into, and fills the flexible hose 105. The second end of the hose 105 connects to the instrument housing 60 and feeds high-pressure air from the hose 105 to a pressure-responsive member 110. The instrument housing 60 may also include a pressure-release mechanism 115 that can be actuated by the user to release high-pressure air from the tire.

The pressure-responsive member 110 includes a hollow C-shaped tube 120 (often referred to as a Bourdon tube) having a first end in fluid communication with the flexible hose 105 and a second end that is sealed and is coupled to a linkage 125. The linkage 125 includes an arm member 130 that is pivotable about both of its ends and a gear member 135. A first end of the arm member 130 connects to the sealed end of the tube 120 and a second end of the arm member 130 connects to an extension that projects from the gear member 135. The gear member 135 engages a second gear 140 that is fixedly attached to the first needle 80 such that rotation of the second gear 140 produces a corresponding rotation of the first needle 80. A biasing member in the form of a torsional spring 145 biases the needle 80 toward its low-pressure position (illustrated in FIG. 2).

While a dial-type pressure gauge and mechanism has been described, one of ordinary skill will realize that other types of pressure gauges (e.g., load cells, capacitive sensors, optical sensors, and the like) could be employed. In addition, other mechanisms or linkages could be employed to measure pressure. As such, the invention should not be limited to only the dial-type gauge and mechanism described.

The depth gauge 70, illustrated in FIG. 3, includes a probe 150 that extends from the housing 60 and is fixedly attached to a rack 155. The rack 155, disposed substantially within the housing 60, engages a first gear 160 that is fixedly supported for rotation. The first gear 160 engages a second gear 165 that rotates in the opposite direction as the first gear 160 in response to movement of the rack 155. A shaft 170 supports the second gear 165 for rotation and also supports the second needle 90. Thus, movement of the probe 150 produces a corresponding movement of the second needle 90.

Referring to FIGS. 2 and 4, the depth gauge 70 also includes a pin 172 that extends above the housing 60. The pin 172 is connected with the rack such that movement of the pin 172 into the housing 60 produces a corresponding movement of the probe 150 out of the housing 60. Probes 150 are commonly biased to their maximum extended position. This position often corresponds with the zero depth measurement. In the illustrated construction, the probe 150 is not biased to any position. Rather, friction within the device assures that the probe 150 does not move unless a sufficient force is applied. Thus, the probe 150 can be positioned within the housing 60 when not in use. Positioning the probe 150 within the housing 60 provides additional protection to the probe 150.

Many different parameters can be measured to indicate the condition of the tire 40. These parameters include, but are not limited to, internal pressure, tread depth, tire thickness, tire resilience, side wall wear, and the like. As such, while the foregoing discussion describes the two gauges 65, 70 as a pressure gauge and a tread depth gauge respectively, other gauges that measure other parameters could be employed.

Turning to FIG. 5, the front of the instrument is shown to better illustrate the faceplate 75. As discussed, the faceplate 75 includes the pressure scale 85 and the depth scale 95. The pressure scale 85 interacts with the first needle 80 to indicate the internal pressure of the tire 40. The scale 85 illustrated in FIG. 5 shows a gauge pressure measured in pounds per square inch (psig). While the illustrated scale 85 indicates a pressure range between 0 and 60 psig, any suitable range (e.g., 0 to 120 psig) could be employed. Of course, other scales could be used in place of, or in addition to, the one illustrated. For example, a scale that indicates absolute pressure (psia) or indicates the pressure in different units (e.g., metric units such as Pascals, kPa) may also be applied to the faceplate 75. In addition, two different units could be applied to the same scale if desired.

The depth scale 95 interacts with the second needle 90 to indicate the depth of the tire tread being measured. The depth scale 95, as illustrated in FIG. 5, includes increments that are labeled as fractions of an inch. Again, other scales (e.g., metric units such as millimeters, mm) could be used in place of, or in addition to, the one illustrated in FIG. 5.

Many different tires 40 can be used on vehicles and motorcycles 10. For example, long life tires can be used on motorcycles 10 that are used for touring. Low-profile tires may be used on motorcycles 10 that are used less frequently. These two types of tires include very different treads. The long life tire, when new, includes a relatively thick or deep tread when compared to a new low-profile tire. As such, a tread depth measurement that indicates one-half of the tread on the long life tire has been worn, may be the same measurement result achieved when measuring the tread of a new low-profile tire. Thus, the actual quantity of tread wear is not indicative of tire life. Rather, the actual tread depth is indicative. No matter the tire employed, a tread depth of about 2/32 of an inch ( 1/16 ) or less indicates a worn tire. Of course some tire manufacturers may indicate that a tire is not worn until the tread depth is less than 2/32 of an inch, or that a tire is worn even when more than 2/32 of an inch of tread remains.

Because a tire with a tread depth of 2/32 of an inch or less is generally considered worn out, the second scale 95 includes a color coding scheme that further indicates the status of the tire's tread. The depths from 2/32 ( 1/16 ) of an inch to zero are located within a first zone 180. The first zone 180 is colored red to indicate to the rider that the tire tread is worn and that the tire 40 should be replaced. A second zone 185 extends from 2/32 of an inch to a predetermined value, such as 5/32 of an inch as illustrated in FIG. 5. The second zone 185 is colored yellow to indicate to the rider that the tire 40 is not completely worn but that it is approaching the end of its useful life. The remainder of the scale 95 makes up a third zone 190. The third zone 190 is colored green to indicate that the tread depth is adequate. Of course, more or less zones as well as a different color scheme or pattern scheme could be employed if desired.

FIG. 6 illustrates another construction of the instrument 200 that also includes a first gauge 65 in the form of a pressure gauge and a second gauge 70 in the form of a tread depth gauge. The pressure gauge and the tread depth gauge are similar to those already described with regards to FIGS. 2-5. However, to further reduce the size of the instrument 200, the construction of FIG. 6 replaces the flexible hose 105 with a short rigid tube 205 that supports the fill valve fitting 50. The elimination of the long flexible hose 105 produces a more compact instrument 200 that is easily stored.

To use the instrument 55 or 200, the user connects the fill valve fitting 50 to the fill valve 45 of the tire 40 being evaluated. A small quantity of the air within the tire 40 flows into the flexible tube 105 (rigid tube 205 in the construction of FIG. 6) and fills the C-shaped tube 120. The high-pressure air tends to straighten the C-shaped tube 120, which causes the first arm member 130 to move, which in turn moves the gear 135. The movement of the gear 135 causes the second gear 140 to rotate a corresponding amount to move the first needle 80. The first needle 80 points to a pressure value, which can be compared to the manufacturer's recommendations to determine if the tire pressure is suited to the particular riding conditions. If the tire pressure is too high or too low, air can be released or added and the measurement can be repeated until the desired pressure is achieved.

The user then extends the probe 150 by pressing down on the pin 172. The probe 150 is then positioned within a tire tread and the housing 60 is moved into contact with the tire 40. The rack 155 moves in response to the probe's contact with the bottom of the tire tread until the housing 60 contacts the outermost surface of the tire 40. Thus, the probe 150 extends beyond the housing 60 an amount that is substantially equal to the depth of the tire tread. The movement of the rack 155 rotates the associated gears 160, 165 to rotate the second needle 90. The user can simply look at which color zone 180, 185, 190 the needle 90 is in to evaluate the tire's tread depth or can look at the actual measurement. Using the instrument 55, 205 as just described provides the user with accurate and useful data regarding the condition of the vehicle's tires 40.

Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims. 

1. A tire maintenance gauge comprising: a first sensor engageable with a tire to measure a first tire parameter; a first indicator movable in response to the measured first tire parameter; a second sensor engageable with the tire to measure a second tire parameter; and a second indicator movable in response to the measured second tire parameter.
 2. The tire maintenance gauge of claim 1, wherein the first sensor includes a pressure sensor.
 3. The tire maintenance gauge of claim 1, wherein the first indicator includes a needle.
 4. The tire maintenance gauge of claim 1, wherein the second sensor includes a depth probe.
 5. The tire maintenance gauge of claim 1, wherein the second indicator includes a needle.
 6. The tire maintenance gauge of claim 1, further comprising a housing, the first sensor and the second sensor disposed substantially within the housing.
 7. The tire maintenance gauge of claim 6, wherein the housing includes a face and the face includes a first scale portion and a second scale portion, the first scale portion cooperating with the first indicator to indicate the first tire parameter and the second scale portion cooperating with the second indicator to indicate the second tire parameter.
 8. The tire maintenance gauge of claim 7, wherein the first tire parameter includes a tire pressure and the second tire parameter includes a tread depth.
 9. The tire maintenance gauge of claim 1, further comprising a conduit having a tire engaging portion disposed at a first end, the conduit providing fluid communication between the tire engaging portion and the first sensor.
 10. The tire maintenance gauge of claim 9, wherein the conduit includes a flexible hose portion.
 11. The tire maintenance gauge of claim 1, wherein at least one of the first and second indicators is coded to associate tire condition with the respective measured parameter.
 12. The tire maintenance gauge of claim 1, further comprising a housing, the first sensor at least partially disposed on a first end of the housing and the second sensor at least partially disposed on a second end of the housing opposite the first end.
 13. A tire maintenance gauge comprising: a housing; a sensor disposed within the housing and operable to measure a pressure; a conduit having a first end connectable to a tire and a second end connected to the sensor; a first indicator needle coupled to the sensor and movable in response to the measured pressure; a probe extending from the housing, the probe movable to measure a depth; and a second indicator needle coupled to the probe and movable in response to movement of the probe.
 14. The tire maintenance gauge of claim 13, wherein the housing includes a face and the face includes a first scale portion and a second scale portion, the first scale portion cooperating with the first indicator needle to indicate the measured pressure and the second scale portion cooperating with the second indicator needle to indicate the measured depth.
 15. The tire maintenance gauge of claim 13, wherein the second indicator is coded to associate tire condition with the measured tread depth.
 16. The tire maintenance gauge of claim 15, wherein the second indicator is coded with a multi-colored scale divided into a first colored region indicating a first magnitude of tread depth, a second colored region indicating a second magnitude of tread depth, and a third colored region indicating a third magnitude of tread depth.
 17. The tire maintenance gauge of claim 13, wherein the pressure includes a tire pressure and the depth includes a tread depth.
 18. The tire maintenance gauge of claim 13, wherein the conduit includes a flexible hose portion.
 19. The tire maintenance gauge of claim 13, wherein the conduit connects to the housing on a first side of the housing and the probe extends from a second side of the housing, the second side opposite the first side.
 20. A gauge for measuring a tire pressure and a depth of a tire tread, the apparatus comprising: a housing: a pressure sensor disposed within the housing; a conduit interconnecting the pressure sensor and the tire such that the pressure sensor measures the tire pressure; a first indicator coupled to the pressure sensor and operable to indicate the measured tire pressure; a probe extending from the housing, the probe having a tip disposed a first distance from the housing; and a second indicator coupled to the probe and operable in response to movement of the probe to indicate the depth of the tire tread.
 21. The gauge of claim 20, wherein the housing includes a face and the face includes a first scale portion and a second scale portion, the first scale portion cooperating with the first indicator to indicate the measured tire pressure and the second scale portion cooperating with the second indicator to indicate the depth of the tire tread.
 22. The gauge of claim 20, wherein the second indicator is coded to associate tire condition with the measured tread depth.
 23. The gauge of claim 22, wherein the second indicator is coded with a multi-colored scale divided into a first colored region indicating a first magnitude of tread depth, a second colored region indicating a second magnitude of tread depth, and a third colored region indicating a third magnitude of tread depth.
 24. The gauge of claim 20, wherein the conduit includes a flexible hose portion.
 25. The gauge of claim 20, wherein the conduit connects to the housing on a first side of the housing and the probe extends from a second side of the housing, the second side opposite the first side. 